/[gxemul]/trunk/src/timer.c
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Contents of /trunk/src/timer.c

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Revision 44 - (show annotations)
Mon Oct 8 16:22:56 2007 UTC (11 years, 9 months ago) by dpavlin
File MIME type: text/plain
File size: 6851 byte(s)
++ trunk/HISTORY	(local)
$Id: HISTORY,v 1.1632 2007/09/11 21:46:35 debug Exp $
20070616	Implementing the MIPS32/64 revision 2 "ror" instruction.
20070617	Adding a struct for each physpage which keeps track of which
		ranges within that page (base offset, length) that are
		continuously translatable. When running with native code
		generation enabled (-b), a range is added after each read-
		ahead loop.
		Experimenting with using the physical program counter sample
		data (implemented 20070608) together with the "translatable
		range" information, to figure out which physical address ranges
		would be worth translating to native code (if the number of
		samples falling within a range is above a certain threshold).
20070618	Adding automagic building of .index comment files for
		src/file/, src/promemul/, src src/useremul/ as well.
		Adding a "has been translated" bit to the ranges, so that only
		not-yet-translated ranges will be sampled.
20070619	Moving src/cpu.c and src/memory_rw.c into src/cpus/,
		src/device.c into src/devices/, and src/machine.c into
		src/machines/.
		Creating a skeleton cc/ld native backend module; beginning on
		the function which will detect cc command line, etc.
20070620	Continuing on the native code generation infrastructure.
20070621	Moving src/x11.c and src/console.c into a new src/console/
		subdir (for everything that is console or framebuffer related).
		Moving src/symbol*.c into a new src/symbol/, which should
		contain anything that is symbol handling related.
20070624	Making the program counter sampling threshold a "settings
		variable" (sampling_threshold), i.e. it can now be changed
		during runtime.
		Switching the RELEASE notes format from plain text to HTML.
		If the TMPDIR environment variable is set, it is used instead
		of "/tmp" for temporary files.
		Continuing on the cc/ld backend: simple .c code is generated,
		the compiler and linker are called, etc.
		Adding detection of host architecture to the configure script
		(again), and adding icache invalidation support (only
		implemented for Alpha hosts so far).
20070625	Simplifying the program counter sampling mechanism.
20070626	Removing the cc/ld native code generation stuff, program
		counter sampling, etc; it would not have worked well in the
		general case.
20070627	Removing everything related to native code generation.
20070629	Removing the (practically unusable) support for multiple
		emulations. (The single emulation allowed now still supports
		multiple simultaneous machines, as before.)
		Beginning on PCCTWO and M88K interrupts.
20070723	Adding a dummy skeleton for emulation of M32R processors.
20070901	Fixing a warning found by "gcc version 4.3.0 20070817
		(experimental)" on amd64.
20070905	Removing some more traces of the old "multiple emulations"
		code.
		Also looking in /usr/local/include and /usr/local/lib for
		X11 libs, when running configure.
20070909	Minor updates to the guest OS install instructions, in
		preparation for the NetBSD 4.0 release.
20070918	More testing of NetBSD 4.0 RC1.

1 /*
2 * Copyright (C) 2006-2007 Anders Gavare. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * 3. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 *
28 * $Id: timer.c,v 1.11 2007/06/18 04:23:19 debug Exp $
29 *
30 * Timer framework. This is used by emulated clocks.
31 */
32
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <signal.h>
36 #include <string.h>
37 #include <unistd.h>
38 #include <sys/time.h>
39
40 #include "misc.h"
41 #include "timer.h"
42
43
44 /* #define TEST */
45
46
47 struct timer {
48 struct timer *next;
49
50 double freq;
51 void (*timer_tick)(struct timer *timer, void *extra);
52 void *extra;
53
54 double interval;
55 double next_tick_at;
56 };
57
58 static struct timer *first_timer = NULL;
59 struct timeval timer_start_tv;
60 static double timer_freq;
61 static int timer_countdown_to_next_gettimeofday;
62 static double timer_current_time;
63 static double timer_current_time_step;
64
65 static int timer_is_running;
66
67 #define SECONDS_BETWEEN_GETTIMEOFDAY_SYNCH 1.65
68
69
70 /*
71 * timer_add():
72 *
73 * Adds a virtual timer to the list of timers.
74 *
75 * Return value is a pointer to a timer struct.
76 */
77 struct timer *timer_add(double freq, void (*timer_tick)(struct timer *timer,
78 void *extra), void *extra)
79 {
80 struct timer *newtimer;
81
82 CHECK_ALLOCATION(newtimer = malloc(sizeof(struct timer)));
83
84 if (freq <= 0.00000001)
85 freq = 0.00000001;
86
87 newtimer->freq = freq;
88 newtimer->timer_tick = timer_tick;
89 newtimer->extra = extra;
90
91 newtimer->interval = 1.0 / freq;
92 newtimer->next_tick_at = timer_current_time + newtimer->interval;
93
94 newtimer->next = first_timer;
95 first_timer = newtimer;
96
97 return newtimer;
98 }
99
100
101 /*
102 * timer_remove():
103 *
104 * Removes a virtual timer from the list of timers.
105 */
106 void timer_remove(struct timer *t)
107 {
108 struct timer *prev = NULL, *cur = first_timer;
109
110 while (cur != NULL && cur != t) {
111 prev = cur;
112 cur = cur->next;
113 }
114
115 if (cur == t) {
116 if (prev == NULL)
117 first_timer = cur->next;
118 else
119 prev->next = cur->next;
120 free(cur);
121 } else {
122 fprintf(stderr, "attempt to remove timer %p which "
123 "doesn't exist. aborting\n", t);
124 exit(1);
125 }
126 }
127
128
129 /*
130 * timer_update_frequency():
131 *
132 * Changes the frequency of an existing timer.
133 */
134 void timer_update_frequency(struct timer *t, double new_freq)
135 {
136 if (t->freq == new_freq)
137 return;
138
139 t->freq = new_freq;
140
141 if (new_freq <= 0.00000001)
142 new_freq = 0.00000001;
143
144 t->interval = 1.0 / new_freq;
145 t->next_tick_at = timer_current_time + t->interval;
146 }
147
148
149 /*
150 * timer_tick():
151 *
152 * Timer tick handler. This is where the interesting stuff happens.
153 */
154 static void timer_tick(int signal_nr)
155 {
156 struct timer *timer = first_timer;
157 struct timeval tv;
158
159 timer_current_time += timer_current_time_step;
160
161 if ((--timer_countdown_to_next_gettimeofday) < 0) {
162 gettimeofday(&tv, NULL);
163 tv.tv_sec -= timer_start_tv.tv_sec;
164 tv.tv_usec -= timer_start_tv.tv_usec;
165 if (tv.tv_usec < 0) {
166 tv.tv_usec += 1000000;
167 tv.tv_sec --;
168 }
169
170 #ifdef TIMER_DEBUG
171 /* For debugging/testing: */
172 {
173 double diff = tv.tv_usec * 0.000001 + tv.tv_sec
174 - timer_current_time;
175 printf("timer: lagging behind %f seconds\n", diff);
176 }
177 #endif
178
179 /* Get exponentially closer to the real time, instead of
180 just changing to it directly: */
181 timer_current_time = ( (tv.tv_usec * 0.000001 + tv.tv_sec) +
182 timer_current_time ) / 2;
183
184 timer_countdown_to_next_gettimeofday = timer_freq *
185 SECONDS_BETWEEN_GETTIMEOFDAY_SYNCH;
186 }
187
188 while (timer != NULL) {
189 while (timer_current_time >= timer->next_tick_at) {
190 timer->timer_tick(timer, timer->extra);
191 timer->next_tick_at += timer->interval;
192 }
193
194 timer = timer->next;
195 }
196
197 #ifdef TEST
198 printf("T"); fflush(stdout);
199 #endif
200 }
201
202
203 /*
204 * timer_start():
205 *
206 * Set the interval timer to timer_freq Hz, and install the signal handler.
207 */
208 void timer_start(void)
209 {
210 struct timer *timer = first_timer;
211 struct itimerval val;
212 struct sigaction saction;
213
214 if (timer_is_running)
215 return;
216
217 timer_is_running = 1;
218
219 gettimeofday(&timer_start_tv, NULL);
220 timer_current_time = 0.0;
221
222 /* Reset all timers: */
223 while (timer != NULL) {
224 timer->next_tick_at = timer->interval;
225 timer = timer->next;
226 }
227 val.it_interval.tv_sec = 0;
228 val.it_interval.tv_usec = 1000000.0 / timer_freq;
229 val.it_value.tv_sec = 0;
230 val.it_value.tv_usec = 1000000.0 / timer_freq;
231
232 memset(&saction, 0, sizeof(saction));
233 saction.sa_handler = timer_tick;
234
235 sigaction(SIGALRM, &saction, NULL);
236
237 setitimer(ITIMER_REAL, &val, NULL);
238 }
239
240
241 /*
242 * timer_stop():
243 *
244 * Deinstall the signal handler, and disable the interval timer.
245 */
246 void timer_stop(void)
247 {
248 struct itimerval val;
249 struct sigaction saction;
250
251 if (!timer_is_running)
252 return;
253
254 timer_is_running = 0;
255
256 val.it_interval.tv_sec = 0;
257 val.it_interval.tv_usec = 0;
258 val.it_value.tv_sec = 0;
259 val.it_value.tv_usec = 0;
260
261 setitimer(ITIMER_REAL, &val, NULL);
262
263 memset(&saction, 0, sizeof(saction));
264 saction.sa_handler = NULL;
265
266 sigaction(SIGALRM, &saction, NULL);
267 }
268
269
270 #ifdef TEST
271 static void timer_tick_test(struct timer *t, void *extra)
272 {
273 printf((char *) extra); fflush(stdout);
274 }
275 #endif
276
277
278 /*
279 * timer_init():
280 *
281 * Initialize the timer framework.
282 */
283 void timer_init(void)
284 {
285 first_timer = NULL;
286 timer_current_time = 0.0;
287 timer_is_running = 0;
288 timer_countdown_to_next_gettimeofday = 0;
289
290 timer_freq = TIMER_BASE_FREQUENCY;
291 timer_current_time_step = 1.0 / timer_freq;
292
293 #ifdef TEST
294 timer_add(0.5, timer_tick_test, "X");
295 timer_add(10.0, timer_tick_test, ".");
296 timer_add(200.0, timer_tick_test, " ");
297 timer_start();
298 while (1)
299 sleep(999999);
300 #endif
301 }
302

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